Analysis of Corticosteroids in Cosmetics by Reversed Microemulsion Electrokinetic Chromatography with 1 Butyl 3 methylimizolium Tetrafluoborate Ionic Liquid as Additive

KeyWord:microemulsion electrokinetic chromatography  corticosteroids  ionic liquid  cosmetics

Abstract:

      A reversed microemulsion electrokinetic chromatographic£¨MEEKC£© method was developed for the separation of three corticosteroids£¬including hydrocortisone£¬prednisone and hydrocortisone acetate by using 1 butyl 3 methylimizolium tetrafluoborate£¨BMIM-BF4£© ionic liquid£¨IL£© as additive.The effects of experimental conditions such as BMIM-BF4 concentration and pH value on separation efficiency were investigated.The optimized conditions were as follows£º2ª±4% sodium dodecyl sulfate£¨SDS£©£¬6ª±6% 1 butanol£¬0ª±5% n octane£¬35 mmol/L BMIM-BF4£¬pH 2ª±2 20 mmol/L NaH2PO4£¬an applied voltage of -20 kV and a detection wavelength of 250 nm.Under the optimized conditions£¬the calibration curves were linear in the range of 5-400,5-400,5-800 mg?L-1 for hydrocortisone£¬prednisone and hydrocortisone acetate with detection limits£¨S/N=3£© of 0ª±9£¬0ª±9,1ª±2 mg/L£¬respectively.The RSDs£¨n=3£© were less than 4ª±3%.The average spiked recoveries were 102%£¬97% and 94%£¬respectively.The results showed that the resolution of the IL-MEEKC method for the separation of hydrocortisone£¬prednisone and hydrocortisone acetate was higher than that of the conventional MEEKC method.The proposed method was simple£¬rapid and effective£¬and could be used for the quality control of cosmetics.